This invention is concerned with mechanical transfer switches to switch loads from one electrical source to another. It is specifically concerned with a power supply transfer switch designed to accommodate very high voltages where the mechanical switch operates electrical contacts to switch an electrical load from one high voltage source to another.
Communication systems having a high reliability requirement may use redundant power or voltage sources wherein one voltage source may be used to replace another voltage source for the purposes of source failure protection and servicing and maintenance of the voltage sources. A typical communication system utilizing redundant high voltage sources is the long distance undersea submarine cable used to provide communication links from one continent to another. The repeater circuits of the submarine cable are powered by the high voltage power sources. At least two high voltage sources are selectively connected to each terminal of the cable so that a main high voltage source is backed up by a redundant high voltage source. A transfer switch is utilized to replace one high voltage source with another. The switching arrangement must accommodate high voltages. In the case of communication transmission facilities the redundant voltage source is connected to the load before the primary voltage source is disconnected to assure continuity of transmission service.
A transfer switch which switches high voltage power must be designed to minimize corona. The transfer switching action must be positive and reliable. The personnel operating the switch must be protected from the high voltage sources by insulation.
A high voltage transfer switch should, in addition to the foregoing features, also act smoothly and be of economical construction without compromising the desired performance.
In the powering of communication systems the transfer switch should transfer the load from one high voltage source to another without introducing service interruptions into the cable transmission system.